|Speaker||Prof. Sung-Gon Kim|
|Date||Thu. 23 Nov. 2017|
|Venue||#331, Asan Hall, College of Science|
“Organocatalytic Cascade Reactions for the Asymmetric Synthesis
of Fused-ring Compounds”
Fused-ring structural units including chroman, indoline, pyrrolidine and hydroqunoline are widely distributed in nature and many biologically active compounds. Molecules containing these structural units exhibit a broad range of bioactivities such as anticancer, antiviral, antitumar, antimicrobial, sex pheromone, and central nervous system activity. Owing to the importance of these class of compounds, the stereoselective synthesis of fused-ring compounds is a noteworthy synthetic goal. In this presentation, we demonstrate the asymmetric synthesis of hydroquinoline, hydroquinazoline, and indolines via catalytic cascade reaction.
First, A synthetic method for the construction of fully substituted enantioenriched 1,4-dihydroquinolines using an organocatalytic aza-Michael/Michael cascade reaction has been developed (Sheme 1). 1 The asymmetric reaction of 2-(tosylamino)phenyl α,β-unsaturated ketones with alkynyl aldehydes, promoted by diphenylprolinol O-TMS ether as an organocatalyst, generated chiral 1,4-dihydroquinolines in good to high yields with excellent enantioselectivities (up to 97% ee)
We have also found a concise synthetic route to valuable highly functionalized benzosulfamidate-fused tetrahydroquinazoline (Scheme 2).2 The [4+2] cycloaddition of o-N-Cbz-amino-b-nitrostyrene with benzoxathiazine 2,2-dioxide using an imidazole as the catalyst afforded tetrahydroquinazolines with high diastereoselectivities.
In addition, we have established the synthesis of chiral benzosulfamidate-fused pyrrolidines through an Mannich/aza-Michael cascade reaction of δ-formyl-a,b-unsaturated ketones with cyclic N-sulfimines (Scheme 3).3 This simple domino process afforded diverse highly functionalized pyrrolidines in good yields with high diastero- and enantioselectivities.
1. Lee, Y.; Heo, S.; Kim, S.-G. Adv. Synth. Catal. 2015, 357, 1545-1550.
2. Sim, J.-T.; Kim, H. Kim, S.-G. Tetrahedron Lett. 2016, 57, 5907-5910.
3. Kim, H.; Kim, Y.; Kim, S.-G. J. Org. Chem. 2017, 82, 8179-8185.
|Notice||Spring semester 2019 Seminar Schedule||-||-|
|65||Fall semester 2018 Seminar Schedule||-||-|
|64||Fall semester 2016 Seminar Schedule||-||-|
|63||Spring semester 2017 Seminar Schedule||-||-|
|62||[Thu. 27 Apr. 2017] Seminar was canceled!||-||-|
|61||Fall semester 2017 Seminar Schedule||-||-|
|60||[Wed. 5 July. 2017] Seminar is canceled!||-||-|
|59||7th Jilin-Korea-Waseda Alliance Annual Symposium||-||August 17 ~ 19, 2017|
|58||[Fri. 13 Oct. 2017] Dr. J. Nathan Hohman/The Molecular Foundry, Lawrence Berkeley National Laboratory, California, USA||Dr. J. Nathan Hohman||Fri. 13 Oct. 2017|
|57||[Fri. 16 Jun. 2017] Prof. Martin Thuo/Department of Materials Science and Engineering, Iowa State University, USA||Prof. Martin Thuo||Fri. 16 Jun. 2017|
|56||[Fri. 17 Mar. 2017] 9th RINS Symposium||-||Fri. 17 Mar. 2017|
|55||[Fri. 30 Oct. 2017] Prof. Igor Rodin/Department of Chemistry, Moscow State University, Moscow, Russia||Prof. Igor Rodin||Fri. 30 Oct. 201|
|54||[Fri. 17 Jun. 2016] Prof. Jianwei Sun/Remote Control in Brønsted Acid Catalysis: New Strategies for the Synthesis of Chiral Building Blocks and Medium Rings||Prof. Jianwei Sun||Friday 17 June 2016|
|53||[January 24, 2018] Electro-Optic Organic THz Wave Sources||Prof. O-Pil Kwon(Ajou University)||January 24, 2018 (Wednesday)|
|52||[March 20, 2019] Challenges in molecular dynamics simulations of unfolded proteins and protein-DNA complexes||Dr. Jejoong Yoo||March 20, 2019|
|51||[March 27, 2019] Hyperpolarization Researches with NV center, 129Xe and Parahydrogen||Prof. Keunhong Jeong||March 27, 2019|
|50||[Mon. 16 Oct. 2017] Prof. Kirk S. Schanze/Department of Chemistry, University of Texas at San Antonio, Texas, USA||Prof. Kirk S. Schanze||Mon. 16 Oct. 2017|
|49||[Mon. 9 Jan. 2017] Prof. Sungwook Woo/Wyss Institute for Biologically Inspired Engineering, Harvard University, USA||Prof. Sungwook Woo||Mon. 9 Jan. 2017|
|48||[Mon. 13 Oct. 2016] Prof. Amir H. Hoveyda/Multicomponent Catalytic Synthesis of Organoboron Compounds for Scalable Natural Product Synthesis||Prof. Amir H. Hoveyda||Monday 13 October 2016|
|47||[November 14, 2017] Zero-Point Energy, Fluctuations, and Dissipation : A (Mostly) Quantum-Optical Perspective||Prof. Milonni, Peter||November 14, 2017|
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